INTEGRATION OF MOCVD AND WET CHEMICAL TECHNIQUES TO OBTAIN HIGHLY ORDERED POROUS ZNO NANOPLATFORMS

Using a successful integration of MOCVD, colloidal lithography and CBD techniques, we assembled large-area, highly ordered bimodal porous ZnO nanoplatforms (Figure 1).1-3 ZnO seed has been deposited by MOCVD at a 400° C-600° C deposition temperature range. Polystyrene (PS) micro-nanosphere lithography has been used to attain fabrication of ZnO nanorods at selective sites by Chemical Bath Deposition. Crystallinity and morphologies of the MOCVD seed layers as well as the reactants used in the CBD nutrient solution strongly impact on the final aspect of the obtained ZnO nanoplatforms. Three different ZnO morphologies4 can be identified after the CBD growth: i) columnar seed layer; ii) nanotubes just below the PS colloids; iii) solid nanorods at the uncovered areas between adjacent spheres. In situ chemical etching provides a general, low-cost and flexible top-down strategy to modify crystal structure, morphology and surface composition. of these ZnO nanoplatforms. In fact, ZnO crystal surfaces exhibit anisotropic behaviour in etchants solutions. The present study gives a great impetus to the fabrication of tunable ZnO nanoplatforms having multiple morphologies and exceptionally high surface areas suitable for application in sensing devices.